Burner



2 Sheets-Sheet 1 o f x f i x l m m n! Ww. lli s n ls L QLOKM'OMDO Nm l l w. ,L oDMM J l" w i. u QQ M I. Y LL n@ 1 ww L k v H. J. DE N. MCCOLLUM y BURNER Filed oct. 16, 1942 Julyl 2, 1946.

H.}J. DE N. MOCOLLUM July z; 194s.

` BURNER FiledOCt. 16, 1942 Patented July 2, 1946 STATES. PATENT oFFicE BURNER Henry J. De N. McCollum, Chicago, Ill.; Thelma l McCollum executrix of said Henry J. De N.

McCollum, deceased Application October 16, 1.942, Serial No. 462,231

7 Claims.

My invention relates to burners and more particularly to means for improving the combustion in burners of the kind used in aircraft heaters and for similar purposes. l

An object of my invention is to provide a burner of the kindadapted for use in aircraft heaters and having new and improved means for providing a more intimate and homogeneous mixture of the fuel and air.

Another object of my invention isv to provide burner carbureting means wherein the air to be without materially increasing its cost or weight.

Other objects and advantages will become apparent as the description proceeds.

In the'drawings:

Fig. 1-is a view showing a longitudinal section of an aircraft heater embodying one form of my invention;

Fig. 2 is an end. view of the carburetor structure of Fig. l and is taken on the line 2--2 of that figure;

Fig. 3 is a view showing a partial, longitudinal section of an aircraft heater embodying a second form of my invention; Fig. 3A,is a transverse section taken on the line 3A--3A of Fig. 3;

Fig. 4 is a view on a, reduced scale showing the manner in which the air is supplied to the carbureting means and the heat transfer means of Fig. 3;

Fig. 5 is an end view of the carbureting means of Fig. 3 and is taken on-the line 5 5 of that ligure; and

Fig. 6 is a view showing a detail and is on the line 6-5 of Fig. 5.

In the embodiment of Figs. 1 and 2, l have illustrated an aircraft heater comprising, in general, a combustion chamber l0 for supplying hot products of combustion to one end of a tubular heat exchanger l2 to which the combustion chamtaken y or in any other suitable manner, as indicatedA at I 6 and I8, to close the ends of the passagesV 2 bustion delivered to the heat exchanger by the combustion chamber.l The ends of the hollow fins are pinched together and sealed by welding in the hollow fins.

The hot productsl of combustion from the combustion chamber lli flow through a taperedanmixed with fuel is preheated to provide a more ber lil is connected by way of an outwardly larextending passages for the hot products of conenular passage 20 surrounding the nose 22 and tapered end 2d 'of a muiller 26 which is located inthe heat exchanger I2. sheet metal shell 28 containing sound absorbing material 30, suchl as glass wool or stainless steel wool. acoustic couplings between the gas passages and the interior of the muiiier and permit the sound to pass into the glass wool and be absorbed thereby.

The end of the tubular heat exchanger I2 which is opposite to the combustion chamber I0 is closed by a plate 34 supporting a'n outlet fitting 36. AA discharge chamber 38 is located between the plate 34 and the adjacent. end oi the mufller 26 -and receives the products of combustion after they have given up'their heat .to the heat exchanger I2. These cooled products. of combustion are then discharged to atmosphere through the -outlet tting 3S and any suitable exhaust pipe connected to the threaded end 40 of this iitting.

The tubular heat exchanger and other parts thus far described are enclosed in a cylindrical casing 42 which cooperates with the heat exchanger l2 to form Ventilating air passages between and around the hollow ns. The righthand end of the casing i2 is connected to an air inlet dil which is supplied with air by a ram,`

blower, or other suitable air circulating means. The ventilating air absorbs heat from the heat exchanger I2 and is discharged from the lefthand end of the casing 42 into the aircraft cabin or other space to Abe heated or into Ventilating ducts for conducting this air to selected locations.

I have provided novel carbureting means for supplying a homogeneous, combustible mixture to the combustion chamber l0. The fuel for this carbureting means is furnished by w-ay of a fuel supply pipe i6 having outlet openings d8 located in the cylindrical chamber 56 of my novel carbureting means. The pipe d6 is connected with a pump or other suitable means which supplies the fuel thereto under pressure at a rate which may be lvaried to conform to the particular conditions underwhich the heater is operating. An appropriate` pumping apparatus is diagrammatically indicated in Fig. 3 and will be referred to The muliler has va Openings 32 in the muilier shell form 3 more-specically in a description of the embodiment shown in that figure.

The chamber 50 is located in a structure 02 having a wall 54 which forms the end wall of the combustion chamber I0. A plurality of vanes 56 are arranged tangentially with the cylindrical wall 59 of the chamber 50, as most clearly shown in Fig. 2, and serve to direct combustion air into wardly'to the' openings 60 leading to the mixing chamber 50. This particular arrangement serves a dual purpose in that the longer travel of the air in contact'with the vanes 50 and wall 54 preheat's this air before it enters the mixing chamber 50. This heated air is flowing in directions tangential to the cylindrical wall 58 of the` mixing chamber 50 and enters this mixing chamber with a whirling motion which produces a better intermixing of the air and fuel and this flow arrangement cooperates with the Dreheating of the air to form a homogeneous, highly combustible mixture in the mixing chamber l0. The combustible mixture formed in the mixing chamber 50 passes into the combustion chamber il through the openings 64 in a spider 60 which supports are-igniter 90. The combustible mixture initially entering the combustion chamber i0 is ignited by one or more electrical igniters 'I0 mounted in the wall I4. The igniter l0 is connected to a suitable source of electrical energy by way oi'- a thermostatic switch which disconnects the igniter from its source when the heater attains normal operating temperature. The reignlter l0 is provided to insure maintenance of combustion after the igniter 10 has beenv discon- .nected from itssource of current.

In Figs. 3A, 4 and 5, I have umstrated modied form of my invention wherein the heater has a combustion chamber 00 connected by a flared,

annular plate 82 to one end of a hollow fin heatexchanger-84 which may be identical with the heat exchanger I2 of the preferred embodiment. A muiller is located in the heat exchanger 04 and this muierli maylikewise be identical with the muiiler`20 of the previous embodiment. In fact the heater of Figs. 3, 4 and 5 may be identical with the heater of Fig. l, except for dinerences herein shown or descri I'he heat exchanger 84 is heated by the hot products of combustion owing lengthwise of the .'-hollow ns and transfers this heat to Ventilating air nowing between the heat exchanger 04 and a cylindrical casing Il which surrounds the heat exchanger and combustion chamber. The lefthand end of the casing 90 may open directly into the aircraft 'cabin or other space to be heated or may discharge the heated Ventilating air into a system of ducts for conducting this. air to selected locations. The :ighthand end of the cylindrical casing Il Vis connected to the conical end Il of an air inlet 92 into which al1- is forced by a ram, blower, or any other suitable air circulating means.

- Part of the air forced into the inlet l2 enters date October 6, 1942, and requires no further discussion herein.

The combustion air which flows pastthe check valve 96 enters a conical extension 98 of the combustion inlet 94 and then passes through the three arcuate inlet openings |00 leading to a heating and mixing chamber |02. The chamber |02 is formed between sheet metal plates |04 and |06, which are secured together by fingers |0l forming integral extensions of the plate |04. These fingers have reversely-bent ends |09 which may be welded, soldered, or otherwise attached to the plate |06.

Fuel is supplied tothe mixing chamber |02 by a fuel supply pipe |00 having outlet openings H0 at approximately the center of the chamber |02. The fuel is ejected from theopenings i|0 under pressure and in the form of a :une spray which mixes with the heated air in the chamber |02 to form a combustible mixture. This combustible mixture passes through the tangentially arranged openings |I2 in a burner tube ||4 and is given a whirling motion as it enters the combustion chamber 00. This whirling motion increases the homogeneity of the mixture so that the combustion chamber receives a uniform, highly combustible mixture which is ignited by one or more electrical igniters H6. ,A Asuitable reigniter |I8 is illustrated as being mounted on the burner tube I|4.

Fuel is forced into the fuel supply pipe |08 by a pumping apparatus ||9 whose rate of fuel d ischarge is responsive to atmospheric pressure and to the velocity head of the air stream in the combustion inlet 94. A pipe |20'has its lower end connected tothe pumping apparatus I|9 and its upper end located in the combustion air inletI 94 and directed toward the entrance to this inlet. A pipe- |22 connects the pumping apparatus H9 with a fuel tank or other' suitable source of fuel supply. .The pumping apparatus H9 may be of any of the usual kinds commonly used in connection with aircraft engine 4carburetorsand since the details of this pumping apparatus form no Dart of my invention, further description is unnecessary.

'Ihe plates |04 and |00 which form the mixing and heating chamber |02 provide a relatively narrow entrance |24. For example, this entrance may have a width of only one-eight of an inch,

|04 may be three-eighths of an inch. 'I'he crowding of the air through this narrow entrance, together with the right angle turn which the air must take in flowing into this entrance, creates a turbulence in the air as it enters the chamber |02 which helps in forming a homogeneous mixture between this air and the fuel sprayed from the openings H0 in fuel pipe |08. This turbulence increases the absorption of heat by the air from the plate v|04 which'also formsone wall of the combustion chamber 80. The mixture formed in the chamber |02 is given. a whirling motion by the tangentially varranged parts at the openings ||2 in the burner tube as this mixture passes into the combustion chamber and this whirling motion increases the homogeneity of the mixture 'whereas the width of the heating and mixing chamber |02 opposite the inner -edge of the plate Both embodiments of my invention have been Y designed to provide adequate preheating of the combustion air and provision for homogeneous mixing oi the air and fuel. These objects have been accomplished by means of simple structures which may be easily manufactured and assembled by mass production methods without adding materially to the Weight of the heater. My invention, however, is not limited. to the particular details illustrated and described but may assume numerous other forms and is to'be construed as including all modifications and variations falling within the scope of theappended claims.l

I claim:

- l. In apparatus of the class described, the combination of a combustion chamber having an end wall formed of material of high heat conductivity and exposed throughout substantially its entire area to the heat in said chamber and having an opening therethrough, a second wall spaced from said rst-named Wall, said walls cooperating t0 form an air passage therebetween along the outer face of said end wall, said air passage having an f inlet adjacent Vthe periphery of said rst-named Wall, means for feeding liquid fuel into said air passage for mixture with the air `herein for movementthrough said opening into said combustion chamber and means for giving a whirling motion to the air and fuel entering the combustion chamber.

2. In apparatus of the class described, the combination of a combustion chamber having a circular end wall, a second wall spaced from said end wall and cooperating therewith to form a plurality of air inlet openings arranged about the periphery of said first-named wall, means for admitting liquid fuel to .the space between said walls for mixing with air entering said inlet openings, a tubular member about an opening through said first named wall providing communication between said spaceand said combustion chamber,

and means comprising tangentially arranged Walls for causing said mixture of air and fuel to have a whirling motion in said combustion chamber.

3. In apparatus of the class described, the combination of a combustion chamber having a circular end wall, a, second wall of smaller diameter spaced from said first-mentioned wall, means forming a cylindrical mixing chamber located between said walls. tangential vanes between said walls for directing combustion air tangentially into said mixing chamber, and means for supplying fuel to said mixing chamber for atomization and mixture with the air in said chamber, said second wall and vanes being integral with saidl end wall.

4. Apparatus of the class described, comprising a cylindrical combustion chamber having an end wall exposed throughout substantially its entire area to combustion occurring in said chamber,

said end wall being composed of material having a high coefiicient of heat conductivity, a second wall spacedfrom said end wall to form a mixing chambenjsaid walls cooperating to form combustion air inlets adjacent the edge of said end wall and a passage in heat transmitting contact therewith, said passage communicating with said combustion chamber and said inlets, liquid fuel supply means discharging intermediate said walls for atomization and mixture of the fuel with the air inrsaid .mixing chamber, and means for giving a whirling motion -to air entering said combustion chamber.

5. In a heatervof the class described, the combination of a combustion chamber having a circular end wall, a second wall spaced from said rst named wall, said wallsbulging in opposite directions adjacent their central portions and cooperating to form therebetween a passage of 6. In apparatus of the class described, the com- `bination of a. cylindrical combustion cham-ber having a circular end wall of high heat conductivity and provided with an opening therethrough at its' central portion, a second Wall spaced from said end wall and cooperating therewith to form an air inlet passage of varying width, means for delivering liquid fuel to said passage coaxially with the opening in said end wall, an electrical l igniter mounted in said end wall and having an axis parallel to the axis of said end Wall, a reigniter coaxial with said end wall, a support for said re-igniter, said support being attached to said end wall andprovided with openings connecting said combustion chamber with said passage, andl fluid guiding means for causing com- 'bustible mixture supplied to said combustion 7 chamber to have a whirling motion about the axis of said re-igniter.

7. In an apparatus of the class described, thel the plate, a tubular member connected with said end wall about the opening thereinfmeans' for spraying fuel into said tubular member .for atomi ization and mixture with the air in said member,

and means comprising tangentially arranged walls for causing said mixture of air and fuel to have a whirling motion in said combustion chamber. 'HENRY' J. DE N. MCCOLLUM. 

